1. Field of the Invention
This invention relates to a method of removing protruding reinforcing fibers from a deflashed, fiber reinforced plastic article. More particularly, this invention relates to method and apparatus for removing the fiber whiskers remaining in the flash area of a deflashed, molded plastic article, the fibers having been used in reinforcing the article.
2. The Prior Art
When articles are molded from thermosets, thermoplastics, rubber and the like, the initial product often has extra material called "flash" attached along the mold parting line. Flash results from that portion of the charge which flows from or is extruded from the mold cavity during molding, and is undesirable on most final products.
The removal of flash, or "deflashing", has been accomplished in many ways, e.g. manual deflashing with razor blades, rotation or shaking with abrasive media to break off the flash, and cryogenic deflashing. In the latter, flash is cryogenically embrittled followed by impact with deflashing media, such as pelletized steel or plastic shot, and/or tumbling. Various types of cryogenic deflashing apparatus are taught by U.S. Pat. Nos. 3,827,186 to Ehnot, 3,909,988 to Kerwin et al., 4,312,156 to McWhorter and 4,519,812 to Brull et al., all of which are hereby incorporated by reference.
Deflashing has been complicated by the inclusion of some types of reinforcing staple fibers in compounds to be molded. When polyester staple fibers are added, the flash itself can be removed, but the molded part is left with polyester fiber whiskers/tendrils protruding at the parting line in the original area of flash. This is not a problem with fiber glass reinforced plastic parts, since the fiber glass easily breaks away during deflashing.
The present invention was developed to overcome the problem of fiber whiskers remaining in the flash area of a plastic part deflashed according to prior art techniques.